The invention relates to a water drain plug for a cavity of a vehicle, in particular for a side sill, comprising a base body which can be fixed in an aperture of the side sill and has an opening in which a sealing element is arranged that is adapted to be moved between a closing position, in which the opening is tightly closed, and an opening position, in which the opening is open.
In the cavities of a vehicle, for example in the side sills, water drain openings are provided in order to drain water that can collect in the cavity. To prevent humidity or dirt from entering the cavity during travel, water drain plugs are provided which can close the water drain opening during travel and open the water drain opening at standstill to drain water collected in the cavity.
The water drain plug has a base body which can be inserted into the aperture of the cavity. A movable sealing element is arranged in this base body and can be moved between a closing position and an opening position. When the vehicle is at standstill, this sealing element is usually maintained in the open position by the force of gravity or a low spring preload, such that water can flow out of the cavity. During travel, the sealing element is moved into the closing position due to pressure differences on the outer side and the inner side of the cavity so that the aperture is tightly closed during the travel of the vehicle and a penetration of humidity or dirt is prevented.
Such a water drain plug is for example known from document DE 10 2007 026 543 A1. Here, the sealing element is mounted centrally on a vertical pin on the base body and is displaced vertically upwards into the closing position. To protect the sealing element, an additional covering element is provided which protects the sealing element against stone impacts, for example. However, the sealing element has a very large resting surface on the base body. This can lead to leaks in case stones or dirt get between the base body and the sealing element. In addition, the complete sealing element is displaced, wherein a clamping of the pin can occur under unfavorable conditions, so that the opening cannot be entirely sealed.